Electkic habimeb



F. w. DAVEY.

-ELECTFHC HAMMER.

APPLICATION HLED SFPTl 19, 1919.

Patented May 10', 1921.

SNN

, UNITED STATES "FREDERICK W.1DAVEY, or BROOKLYN, NEWfYoRK.

To all whom it magz/ concern.'

PATENT OFFICE.

ELECTRIC Heini/IER.l f

Ble; it known that I, FREDERICK W. DAVEY, acitizen of the United States,residinofin Brooklyn, inthe county of Kings and tate rof New York,have'invented certain new and useful Improvements in Electric Ham mers,of which the following isa specication. 1

This invention relates to Yelectric harnmers of the type in which thehammer' or plunger'memher is reciprocated byv means of electricsolenoids which are alternately energized for drawing the reciprocatingmember back and forth. f

kas the description proceeds; and while herein minute details oftheinventionv are'described, vthe invention is not limited to these, jsince many and various changes maybe `nism is shown in connection withan elec- The objects of the invention are to provide an eilicientarrangement for reciprocating the hammer member, and vto provide j meansfor moving the lhammer member from neutral position during the startingof the loperation thereof. l'

Anotherobjcct is to provide an arrangement whereby the reciprocating`member will be prevented from becoming permanently maonetized. l

ther objects of the invention will appear lmade without departing fromthe scope of the, invention as claimed. l

` In the accompanying drawing, showing by way of example, one of manypossible embodiments of the invention,-

Figure 1 isa central longitudinal Asectional viewy showing the operatingand controlling mechanisms ofthe hammer;

Fig. 2 is' a sectional view taken on the line A-Bof Fig.` 1; E

Fig. 3 is'fragmental perspective view of the yreciprocatingplunger/member; and j Fig. l is a fragmental elevation', partly insection, showing 'a detail of vthe hammer starting, switch.

` Vhil'e my improved reciprocating mechatric hammer, itis understoodthat itV may be used in connection with many otherldevices in which amember has to be reciprocated.

yIn the'present instance, the reciprocating 'mechanism is shown embodiedyin an electrical hammerprovided' with a cylindrical casing 5in theforward end of which is secured a forward head vvo' provided with anaxial guide bore 7. ,In .the rear of said casing there is secured a rearhead 8 provided with Specication of letters Patent. Patented lay 10, 192L Application filed September 19, y1919. Serial No. 324,755. v' y vahandle 9. In said guide bore 7 there is loosely received the reduced end10 of atool Vspindle 11, said reduced end projecting into the casingchamber formed by said cylindrical ycasing and head;

Intermediately of said chamber ythere is' disposed ka disk 12 of toughinsulating material yprovided with an angular central opening 13 (Fig.2), and a plurality oi ra- .dial `bores 14e' connecting' with saidcentral opening and disposed at right angles to each other... Said diskis held in place between a plurality of lugs 16 by screws 17 passingfrom the outside through said 4lugs and into ythe disk. g

A guide tube 19 of bronze or other desired f non-magnetic material andofsquare internal cross-section passes through said angular opening andterminatesnear said head. Forward and rear solenoids'20 and 21 aredisposed on said tuhe against said disk and are wound and connected upso as to have their like' poles adjacent,A for instance as shown, thevletters S placed near the inner end of keach solenoid, and the`letters Nplaced near the outer ends of the solenoids indicating that these may beeithernorth 'or 'south' poles respectively. The object of this will bepresently explained'. End disks 22 placed near the endsy ofthe guidetubehold thesolenoids in place.

A rubber buffer 24 is disposed within said guide tube 19 against therear head 9; and within said tube, between said buffer andthe 'toolspindle 1l, there isslidably disposed a reciprocating member orplunger-26 (Fig.

Vopenings 'are contact plates 31 held in place by meansoi` front andrear rivets 32 and 33 passing through said transverse Aopenings and saidcontacts and electrically connected contacts of each pair witheachother.

In each of said radial openingf's'lllk there is slidably disposed acarbonlbrush 34.- (Fig. 2), adapted to pass through the openings 35 inthe'tube 19 and engage said contactplates 3l. Each brush is providedwith a contact stem 36 projecting'at the outer ends of the radial bore.A screw plug 38 closes 'the outer end of each radial bore and isprovided with a central perforation through which said stem passes. Ahelical spring v39 Vcompressed between the f/plug and brush posed in theouter end of said switch receiving bore, and is held in place by meansof a shoulder screw plug 43 11i-the outer end of said bore and having avlarge central ope-ning through which passes ,a push-but-v ton 50provided with aflange engaging the inner face of said shoulder plug toprevent the entire removal of the button.v A switch blade 52 screwed tosaid button passes through aslot in the central wall of said cup and isadapted when the buttonV is pressed inwardly against the action'of the Yspring 53 to engage between and electrically connect said springcontacts 45 and 46.

An insulating block 55 is mounted across the interior of saidV bore andhas mounted thereon a conducting piece 56 connected by means of the mainconductor 57 to aterminal 56 engaged by nuts 5901i the end of the stem36 of one of the brushes. A branch. conductor 6l connects said mainconductor with the stem 36 of one of the adjacent brushes.

The other brushes opposite to Y said adjacent brushesare connectedrespectively by means of conductors 62 and 63 to one end of the frontand rear. solenoids 20- and`2l in such manner that the rearvcontactplates may be electrically connected with the rear solenoidswhen theplungergoes forward as shown in Fig. l, and the forward contact platesmay be electrically connected with the forward solenoid when the plungermoves to the rear.' Conductors 65 connect the other ends of the solenoidwireswith the spring contact 46; and a conducting member 6r connects theother contact kmember 45 with one terminal of a source ofcurrent 70,-the other terminal of which source is connected by means of aconductor 7l with said conducting plate 56.

`From the aboveit will be seen that when the plunger is in the forwardposition as indicated in Fig. l, and the button 50 is pressed by thehand of the operator', the current passes from the source of currentthrough the conductor 7l, the conducting piece 56, the main conductor57, brush 34, the rear connecting rivet 33, the opposite brush 34,

the conductor 63, the solenoid 2l, the conductor 65, the spring contact46, the switch blade 52, the other contact 45, and the conductor y67 tothe other terminal of the source of current; This causes the current toenergize Vthe rear solenoid 2l whereupon the plunger 26 is drawn to itsrearmost position, and the forward rivet 32 is brought into contact withthe brush 34 so that the current passes through the branch conductor 61,and the conductor 62, and the forward solenoid 20, thus energizing theforward solenoid and carrying the plunger forward to strike' the toolspindle l1 to operate the tool. This operation is then continued so longas the button 50 is pressed. f Y

As was noted, the solenoids 20 and 21 are wound to have their like polesadjacent, and therefore their magnetic flux flowing in Voppositedirections, The plunger 26, there- 1the* plunger from becomingpermanently mavnetizedfin either direction' and in this way one avoidsthe disadvantage of having Vthe plunger to adhere too strongly to thetool spindle when in the position of Fig; 1.

It sometimes happens, particularly when the hammer is placed inhorizont-al position that the plunger disposes itself at a midpositionso that neither rivet 32 nor 33 is in registration with the brushes,thereby preventing the passage ofany current through the solenoid coils.,p l

In order surely to move ythe plunger to one of its limitsofmovementiwhilestill holding the hammer in horizontalV position, I haveprovided the following starting means: A transverse switch receivingrecess 75 (Fig. 4), formed inthe forward part of the handle 9, isprovided with an'insulating bushing 76 andhas disposed therein a pair ofspringv contacts 7 7v and 7 S mou-nted upon an insulatingsupport 79. nAn independent startingA coil, wound with the solenoid coil 2 1, butentirely electricallyindependent therefrom, has one of its ends 8lelectri- (Fig. 4), secured to the starting button 86 v is pressedinwardly, by the operatorsithumb,

against the action of the spring 87,V it wil-l electricallyl connectsaid Contact members 77 `and 73, thus causing the flow of currentlthrough the conductor 71,' the conducting piece56,`the main conductor`57, the end 81., i

the starting coil, the otheriendr82. of `the starting "coil, the switch`members V77 and 73, and the conductors 83 and 67, thereby lcompletingal circuit through the starting coil drawing the plunger to itsrearmostv position whereupon a circuit .is established through theforward rivet 32', whereupon,

after the starting button is released, the

plunger reciprocates as explained before. I claim: f

' 1. EIn combination, a plunger reciprocat` ablewithinlimits, solenoidmeans for reciprocating said plunger and meansfor moving the plungerwhen in a neutral position between said limits for reciprocation by saidsolenoid means.v y vo f 2. Incombination, a plunger reciprocatablewithinlimits; solenoid means for reciprocating the plunger; andmeansindependent of the solenoid means for moving the plunger when in aneutral position between said limits for reciprocation by said solenoidmeans. y y u 3. In combination, .rco-axial. solenoids; a plungerreciprocatable by ysaid solenoids in the solenoids and within limitsmeans for alternately energizing the solenoids; and means for moving theplunger when in a -neutral position between said limits forreciprocation by'said solenoids.

4.' In`r combination, co-axial solenoids; a plunger reciprocatable bysaid solenoids in the solenoids and'vwithin limits gwmeans foralternately energizing the solenoids; means `independent of saidsolenoidsI for moving `the plunger when in aneutral position betweensaid limits forreciprocatron by said solenoids and electricallyindependent therej from.

6. rIn combination, a pair of co-axial solenoids; a plungerreciprocatable by said solenoids in the solenoids and within limits;means for alternately energizing the solenoids; means independent ofsaid solenoids for moving the plunger when in a neutral position betweensaid limits for reciprocation by said solenoids; means for energizingsaid independent means; and means for o erating said independent means;said in ependent means comprising a coil wound with one of saidsolenoids and electrically independent therefrom.

7. In combination, forward and rearward solenoids; a plungerreciprocatory by said solenoids; means controlled by the plunger forenergizing the solenoids when the plunger moves to one limit or theother;

and separately controlled means `for energizingonesolenoid when theplunger vis between limits." f

8. 'In combination, forward and rearward solenoids; aplungerreciprocatable iin said solenoids; insulating means around said`plunger; conducting means passing through saidfplunger; brushesforvcontacting with said nconducting means; a main conductor connectedto adjacentbrushes; conductors connecting the remaining?` brushes withone end of said frontk and rear solenoids respectively,-in such mannerthat thek forward solenoidis electrically connected tor said mainconductor when the plunger is in rearposition andthe rearward solenoidis connected yto the main conductor when the plunger is in forwardposition; additional conductors connected to the otherv ends of Lsaidsolenoids; and a source of current having one -terminal connectedto theadditional conductorsand its other terminal connected to'said mainconductor. l f' 9. In combination, forward and rearward solenoids; aplunger reciprocatory in.- said solenoids; 'insulatingy means". aroundsaid plunger` and carriedL thereby; conducting members passingtransversely throughv saidk plunger; brushes yieldably held inposition nto `contact ,saidj conductingmembers ay main conductor connected toadjacent brushes; yconductors yconnecting' the 'otherbrushes with oneend of` said front and rear solenoids respectively, in such manner thatthe front Vsolenoid is electrically connectedv to' said main conductorWhenthe plunger is; in rear position and the rear solenoid is connectedto the main Lconductor `when the plunger is in` forward position;additional'v conductors 'connected to the `other yends of said`solenoids; and a source of current having one terminal connected to theadditional conductors and its other terminal connected to said mainconductor. y n

10. In combination, forward and rearward solenoids; a plungerreciprocatory by said solenoids; forward and rear conducting memberspassing through said plunger and arranged in staggered relation to eachkioo iio

other; brushes held in positionto contact opposite ends of saidconducting members; a main conductor connected to adjacent brushes;conductors connecting the other brushes with one end of the wires ofsaid front andrear solenoids respectively, in such when the plunger isin forward position; y

additional conductors connected to the other ends of said solenoids; anda source of current having one terminal connected to the additionalconductors and its other terminal connected to said main conductor. j

11. In combination` forward and rear soleiioids; a plunger reciprocatoryvbylsaid solenoids; forward and rear conducting members passingtransversely through said plunger and arranged in staggered relation toeach other; brushes between said solenoids and yieldably held inposition to contact said conducting members; a main conductor connectedto adjacent brushes; conductors connecting the other brushes with oneend of the wires of .said front and rear solenoids respectively, in suchmanner that the front solenoid is electrically connected .to said mainconductor when the plunger is in rear position and the rear solenoid is4connected 4to the main conductor when the plungergis in forwardposition; additionalconductors connected to theother ends ofsaid'solenoids; and a source of current having one terminal connected tothe additionalcon- `held'against rotation thereing. forward and rearconducting rivets passing transversely through said plunger and arranged1n staggered relation to each other pairs of brushes varranged betweensaid solenoid, one pair to each rivet, and yieldably held-in position tocontact the opposite ends of said rivetsgia main *conductor connectedlto` one brush of each pair; conductors connecting the other brushes withone end of said front and rear solenoidsrespectively, in such mannerthat the Vfront VsolenoidV is electricallyconnected to said mainVconductor when the plunger is in rearposition andthe rear f solenoidisconnected to they main conductor when the plunger vis inforwardposition; ad-

Y additional conductors and its other terminaly connectedto said mainconductor.

13. In combination, a .disk of insulating material provided withycentral opening and radial bores; a guide tube of anguilar in- `ternal`cross-section passing through said opening;v forward and rear solenoidsdisposed on said tube against said disk; aplunyger ofi angularciiosssection slidable in said tube, forward and rear conducting rivetsApassing transversely through said plunger and arranged in staggeredrelation to'each other and 'adapted to come in'register with saidradialbores; an insulating bushing cov- Hering ysaid plunger; brushesslidablein said radialfbores and'yieldably` held in position `to contactsaid rivets ;V a main conductor con- -nected to adjacent brushesconductors connecting the other brushes with one endof i ,saidfrontandrear solenoids respectively, in :such manner thatthe. front solenoid iselectrically connected tosaid main conductor when theplunger is-inrearposition and the V'rear solenoid is connected to the main lcon--ductoriwheny the Aplunger is inforwardposi- L Y"tion additionalconductors connected to the other ends of said solenoids; and asourceofcurrenty having one terminal connected to thefadditional conductors anditsotherA terv V-minal connected to 'said main conductor.

FREDERICK W. DAVEY..A WVitnesses: i H. D. Pennisi', Y Y

H. M. Kinrn'riiioin e

